Device for preventing sediment build-up in gas water heaters

ABSTRACT

The invention relates to gas water heaters whereby, means on the inner end of the cold water inlet are arranged so that the jet of water issuing therefrom is directed tangentially with respect to the vertical axis of the tank to prevent a build-up of sediment on the bottom of the tank.

United States Patent 11 1 1111 3,762,395 Taylor 1 Oct. 2, 1973 [541 DEVICE FOR PREVENTING SEDIMENT 1,978,015 10/1934 Erdman 137/590 X BUILDJJP [N GAS WATER HEATERS 2,896,862 7/1959 Bede 137/392 X 3,016,885 1/1962 Vandcnburgh et a1. 122/17 [75] Inventor: Thomas B. Franklin Taylor, 1,416,487 5/1922 Mauck 126/361 x lslingtomOntario, Canada 72,760 12/1867 Steeger.... 126/361 3,465,123 9/1969 Harris 126/361 X [73] Ass1gnee: Anthes Eastern L1m1ted,T0r0nto O t i C d FOREIGN PATENTS OR APPLICATIONS Fied: Feb. 25,1971 273,418 4/1930 Italy 122/17 1 PP ,716 Primary Examiner-William F. O'Dea Assistant Examiner-William C. Anderson [30] Foreign Application Priority Data Attorney-Thomas Marsha Mar. 4, 1970 Canada 076454 [57] ABSTRACT [52] U.S. Cl. 126/350 R, 126/361 The invention relates to gas water heaters whereby, [51] Int. Cl. F2411 l/00 means on the inner end of the cold water inlet are ar- [58] Field of Search 137/590, 592; ranged so that the jet of water issuing therefrom is di- 350 17 rected tangentially with respect to the vertical axis of the tank to prevent a build-up of sediment on the bot- [56] Reterences Cited tom of the tank.

UNITED STATES PATENTS 7 Claims, 13 Drawing Figures 1,768,039 6/1930 Eiermann 126/361 X 2,504,092 4/1950 Thomas 122/17 PATENTEUBBT e SHEET 10F 2 PRIOR ART FIG. I

PRIOR ART DEVICE FOR PREVENTING SEDIMENT BUILD-UP IN GAS WATER HEATERS This invention relates to storage type gas water heaters. In most known types of such heaters, sediment is apt to collect on the bottom of the tank, the sediment either entering with the cold water, or being precipitated from the hot water or being due to the electrochemical action of the heating anode.

In most conventional centre flue storage type gas water heaters, cold water is introduced into the heater tank from the top thereof and is conducted down to a point adjacent the bottom of the tank through the intermediary dip-tube. The hot water outlet in such heaters is also usually located at the top of the tank. Due to the position of the dip-tube and due to the latter having a generally straight internal bore, water currents are created adjacent the bottom of the tank by the inrush of cold water and this results in the sediment collecting to one side of the flue tube and diametrically opposite to the location of the lower end of the dip-tube. This sediment gradually builds up to a considerable depth whilst spreading horizontally so that it may eventually cover the entire bottom of the tank.

Collection of the sediment on the bottom of the tank is extremely disadvantageous because if only a portion of the bottom of the tank is covered by the sediment, the glass liner at this location tends to become thin. Hence, where the glass liner is thinner, a greater rate of current flowing from the anode will result, thereby shortening the useful life of said anode. This shortening of life will increase as the sediment spreads out horizontally and as the area of thinning glass grows in size.

Moreover, if the water is such that the anode cannot prevent rust appearing on a bare spot, then corrosion will occur and this may well perforate the bottom head thereby imposing a leakage problem. Even if the anode can prevent rust from forming, its life will be considerably shortened whereupon rust will begin on any bare spot and the tank will rust through.

The collection of sediment poses yet another disadvantage in that the water in some geographical areas contains a high content of sediment so that when the gas burner ignites, an audible banging sound is heard emanating from the heater due to the water located beneath the sediment becoming overheated and being converted into steam which boils up through the sediment into the cooler water above, where, at this point, the steam bubbles collapse thereby creating the sharp banging sound.

The only means available for ridding the tank of this sediment is through the intermediary of a drain cock normally located adjacent the bottom of the tank and near the lower end of the dip-tube. However, it quite often happens that the current of water issuing from the lower end of the dip-tube will only clear the sediment adjacent the bottom of said tube, the remainder of the sediment in the tank being untouched.

Hence, it is the object of the present invention to overcome the above disadvantages by providing a simple and inexpensive device within a gas water heater and which device is relatively simple in construction and inexpensive to manufacture.

Accordingly, the present invention relates to a gas water heater including a water tank, a cold water inlet tube leading into said tank and having its inner end located adjacent the bottom of the tank, and means on said inner end for directing the flow of cold water therefrom at least tangentially with respect to the vertical axis of said tank.

The invention is illustrated by way of example in the accompanying drawings in which:

FIG. 1 is a diagrammatic vertical section taken through a prior art type of has water heater and showing the sediment in situ;

FIG. 2 is a transverse section taken on line 22 of FIG. 1;

FIGS. 3, 4 and 5 are detail views of alternative embodiments of a dip-tube constructed in accordance with the invention;

FIG. 6 is a transverse section of a gas water heater showing the invention in situ;

FIGS. 7 10 are diagrammatic views of alternative forms of flue tubes formed integral with the bottom of the tank of the heater; and

FIGS. 11 13 are diagrammatic views of various shapes of tank bottoms and where the flue pipe has been omitted.

Referring to the drawings, and in particular, to FIGS. 1 and 2, which show a prior art or normal type of gas water heater, a glass lined water tank 1 is provided, said tank having a vertically extending flue pipe 2 concentrically arranged therein and a bottom 3. A gas burner 4 is located beneath the bottom 3 and below the lower end of flue 2. A cold water inlet 5 located at the top of the tank serves as the mounting for a downwardly extending dip-tube 6, the lower end of which terminates a predetermined distance from the bottom 3 of the tank 1. The top of the tank 1 also serves as the location for a hot water outlet 7 and, as will be seen from FIG. 2, a magnesium anode 8 is suspended from the top of the tank. The accumulation of sediment 9 in the prior art tanks is also shown and, as will be particularly seen from FIG. 2, such sediment is apt to collect on the bottom 3 of the tank 1 at a point diametrically opposite to the dip-tube 6 and drain-cock 10. Hence, and with the known type of water heaters, even if the drain-cock 10 is opened, the cold water issuing from the lower end of the dip-tube 6 is insufficient to move the sediment out from the drain-cock mainly because the flow of water is in a downward direction.

It has been found by experience that if the lower end of the dip-tube 6 is arranged so that the cold water issues at least tangentially, this is sufficient for it to commence a swirling action so that the sediment is flushed from the tank through the drain-cock 10 when the latter is opened. Hence, FIG. 3 shows the lower end of the dip-tube 6 curved, as at 11, whereby the flow of cold water will be directed at least tangentially with respect to the vertical axis of the tank. Alternatively, and as is shown in FIG. 4, the lower end of the dip-tube 6 is provided with a radial constriction 12 so that the tangential flow of cold water will be of greater velocity. More particularly, referring to FIG. 4, note that the lower end of the dip-tube 6 is generally horizontal and includes a constriction designated by the numeral 12' intermediate the horizontal portion of the dip-tube 6, with the extreme end of the dip-tube being an enlarged opening 12" whereby the lower end of the dip-tube 6 defines a venturi for accelerating the flow of cold water issuing from the dip-tube 6.

Alternatively, and as is shown in FIG. 5, the lower end of the dip-tube 6 can be closed and, adjacent said closed end, a circumferential slit or slot 13 provided.

Of course, the invention is not limited to the type of orifices described above and illustrated in FIGS. 3 5 and they may take other forms without departing from the spirit of the invention providing, of course, that the cold water issuing from the dip-tube 6 is directed at least tangentially with respect to the vertical axis of the tank.

Of course, although the invention has been described and illustrated as being applied to vertical dip-tubes, it is possible to adapt the invention to horizontal cold water inlet tubes.

The effect of such an arrangement is clearly shown in FIG. 6 where, as is indicated by the arrows A, the cold water flows around the flue pipe 2 scouring the sediment from the bottom 3 of the tank 1 and through the drain-cock 10.

Of course, it is within the scope of the invention to change the position of the flue pipe 2 with respect to the bottom 3 of the tank 1 and, moreover, to change the shape of said bottom 3. For instance, and as will be seen from FIG. 7, the flue pipe 2 is concentrically arranged within the tank 1, the horizontal plane of said bottom 3 being normal to the vertical axis of the flue pipe. Alternatively, and as is shown in FIG. 8, the vertical axis of the flue pipe 2 can be arranged so that it is eccentric with respect to the central vertical axis of the tank, the plane of the bottom 3 again being normal to said last-mentioned axis.

If desired, and as is shown in FIG. 9, the vertical axis of the flue tube 2 may be concentric with respect to the central vertical axis of the tank and the bottom 3 of the tank angulated with respect to said last-mentioned axis. As in shown in FIG. 10, the flue pipe may be concentric with respect to the central vertical axis of the tank and the bottom 3 may be convex adjacent the wall of the tank and concave adjacent to its junction with the bottom of the flue pipe 2. Alternatively, and if desired, the flue pipe may be dispensed with entirely whereupon the bottom 3 of the tank can take any of the forms shown in FIGS. 11 13. As will be seen from FIG. 11, the bottom 3 of the tank can be planar or it can be convex as is shown in FIG. 12 or it can be convex as shown in FIG. 13.

As will be appreciated, the disposition of the flue pipe 2 and the shape of the bottom 3, and as shown in FIGS. 7 10, will, together with means provided on the lower end of the dip-tube 6, materially assist in preventing the build-up of sediment on the bottom of the tank and will assist in the general flushing system. The same is true, of course, with the various shapes that the bottom of the tank may take and shown in FIGS. 11 13.

I claim:

1. A gas water heater including an upstanding cylindrical water tank having a generally vertical central axis and a draincock located adjacent the bottom of said tank, a fixed cold water inlet tube leading into said tank and having its inner end located adjacent the bottom of the tank, said inner end being generally horizontal and shaped to include an intermediate venturi portion leading to an enlarged opening of said inner end, the horizontal inner end being disposed at an angle with respect to said central axis for directing the flow of cold water therefrom tangentially with respect to the vertical central axis of said water tank to thereby prevent a build-up of sediment on the bottom of the tank.

2. A gas water heater according to claim 1, including a vertically extending flue pipe within said tank, the plane of the bottom of said tank being normal to the vertical axis of said pipe.

3. A gas water heater according to claim 1, including a vertically extending flue pipe within said tank, the plane of the bottom of said tank being angulated with respect to the vertical axis of said pipe.

4. A gas water heater according to claim 1, including a vertically extending flue pipe within said tank, the bottom of said tank being convex as it approaches the wall of said tank and being concave as it approaches said flue pipe.

5. A gas water heater according to claim 1 wherein the plane of the bottom of the tank is normal to the vertical axis of the latter.

6. A gas water heater according to claim 1 wherein the bottom of the tank is convex.

7. A gas water heater according to claim 1 wherein the bottom of the tank is convex as it approaches the wall of said tank and is concave as it approaches the centre of said tank. 

1. A gas water heater including an upstanding cylindrical water tank having a generally vertical central axis and a draincock located adjacent the bottom of said tank, a fixed cold water inlet tube leading into said tank and having its inner end located adjacent the bottom of the tank, said inner end being generally horizontal and shaped to include an intermediate venturi portion leading to an enlarged opening of said inner end, the horizontal inner end being disposed at an angle with respect to said central axis for directing the flow of cold water therefrom tangentially with respect to the vertical central axis of said water tank to thereby prevent a build-up of sediment on the bottom of the tank.
 2. A gas water heater according to claim 1, including a vertically extending flue pipe within said tank, the plane of the bottom of said tank being normal to the vertical axis of said pipe.
 3. A gas water heater according to claim 1, including a vertically extending flue pipe within said tank, the plane of the bottom of said tank being angulated with respect to the vertical axis of said pipe.
 4. A gas water heater according to claim 1, including a vertically extending flue pipe within said tank, the bottom of said tank being convex as it approaches the wall of said tank and being concave as it approaches said flue pipe.
 5. A gas water heater according to claim 1 wherein the plane of the bottom of the tank is normal to the vertical axis of the latter.
 6. A gas water heater according to claim 1 whereiN the bottom of the tank is convex.
 7. A gas water heater according to claim 1 wherein the bottom of the tank is convex as it approaches the wall of said tank and is concave as it approaches the centre of said tank. 